Blue sulfur dye and process of making same.



UNTTED STATES PATENT FFICE.

RENE BOHN, OF MANNHEIM, GERMANY, ASSIGNOR TO THE BADISOHE ANILIN ANDSODA FABRIK, ,OF LUDWIGSHAFEN, GERMANY.

BLUE SULFUR DYE AND PROCESS OF MAKING SAME.

SPECIFICATION forming part of Letters Patent No. 667,486, dated February5, 1901.

Application filed September 6, 1900.

To all whom it may concern.-

Be it known that I, RENE BOHN, doctor of philosophy and chemist, acitizen of the Swiss Republic, residing at Mannheim, in the Grand Duchyof Baden, Germany, have invented a new Blue Dye and Process of MakingSame, of which the following is a specification.

This invention relates to the production of new blue coloriugmatter from1.5-dinitronaphthalene. This new coloring-matter can be obtained bytreatment of 1.5-dinitro-naphthalene in the presence of sulfuric acidwith hydrogen sulfid. It may also be obtained by passing hydrogen sulfidinto a naphthazarin melt prepared in the well-known manner, preferablyif it be heated to about one hundred and thirty (130) degreescentigrade.

In the following example I illustrate the nature of this my invention,but do not wish to be understood as limiting it to this. The parts areby weight.

Example: Mix one hundred (100) parts of 1.5-dinitro-naphthalene with twothousand (2,000) parts of sufuric acid of ninety-six (96) per cent. H 80in an iron vessel. to one hundred and thirty (130) degrees centigradeand pass into this a current of hydrogen sulfid while stirring. Duringthe course of the reaction a test portion of the melt can be dissolvedin water, giving a blue solution, and soon thereaftenas a test willshow, the melt becomes insoluble in water. This point is usually reachedin the course of from eight (8) to ten (10) hours. 0001 the melt andpour into ten thousand (10,000) parts of water. Filter and wash.

My new coloring-matter in the dry state is a blue-black powder. In theform of a thirty (30) per cent. paste with water it possesses a bluecolor and is soluble in hot water, giving a green-blue solution, whichsolution when made alkaline with sodium carbonate or caustic soda doesnot change in color.

In dilute Heat this Serial No. 29,154- (No specimens.)

caustic-soda solution it dissolves, giving a green-blue solution. Withdilute carbonateof-soda solution it givesagreen-blue solution, a browncolor with concentrated sulfuric acid, and ablue-violet withnitro-benzene. Heated with a solution of sodium bisulfite ofthirty-eight (38) degrees Baum it gives a red-brown solution. With thewell-known reducing mixture of tin salt (stannous chlorid) andhydrochloric acid it gives a brownyellow solution, which on addition often (10) volumes of water yields a yellow precipitate.

My new coloring-matter dyes unmordanted wool a blue color, which aftertreatment with potassium bichromate changes to a green.

What is claimed is 1. The process of making blue coloring- 6o matterwhich consists in treating 1.5-dinitronaphthalene with sulfuric acid anda sulfid, all substantially as described.

2. The process of making blue coloringmatter which consists in treating1.5-dinitronaphthalene with sulfuric acid and hydrogen sulfid, allsubstantially as described.

3. As a new product the blue coloring-matter which can be derived from1.5-dinitronaphthalene, sulfuric acid and hydrogen sul- 7o fid, whichgives a green-blue solution in water which solution when made alkalinewith caustic-soda solution is not changed in color; it gives a browncolor with concentrated sulfuric acid, a blue-violetwith nitro-benzeneand dyes wool a blue color which when treated with potassium bichromatechanges to green, all substantially as described.

In testimony whereof I have hereunto set my hand in the presence of twosubscribing witnesses.

RENE BOHN.

W'itnesses:

JAooB ADRIAN, H. W. HARRIS.

